1. Field of the Invention
The invention relates to a lighting module or a lighting unit for a headlamp of a motor vehicle.
2. Description of the Related Art
The lighting modules of the prior art generate a beam making it possible to produce a light beam allowing the road to be lit, doing so alone or in combination with the beam or beams of other modules. They usually comprise an assembly of associated optical elements in order to form the beam. Some of these beams are cutoff beams, notably of the fog lamp or dim type. Certain modules, generating cutoff beams, use imaging lenses and a folding element, that is to say a reflective plate or horizontal reflective mask in order to create the cutoff.
Bifunction lighting modules are also known, notably according to FR 2 860 280, which is equivalent to U.S. Pat. No. 7,156,544, or according to U.S. Pat. No. 7,387,416.
In certain bifunction modules, the folding element is used both for the upper cutoff of the dim beam and for the lower cutoff of the additional beam, making it possible, in association with the dim beam, to produce a high beam. The image of the front edge forms an obscure separation line between the beams given by the two emitters in order to produce the high beam. In order to prevent this dark band, provision has been made to make the common cutoff indistinct by unfocusing the folding element or the lens, or by adding images to the latter. The fusion of the two beams, carried out by virtue of indistinct zones, also leaves a darker zone between the two beams. The modifications attempting to make the cutoff indistinct reduce the value of the maximum intensity of the high beam. These drawbacks are present in the beams produced with the devices of the two patents mentioned above.